1. Field of the Invention
The present invention relates to a paper feed cassette for stocking paper to be sent to the printing part of an image-forming apparatus. More particularly, the present invention relates to a paper feed cassette having a function as a catch tray for receiving paper ejected from the paper ejection port of the image-forming apparatus.
2. Background Information
FIG. 4(a) shows a schematic side view of an example of conventional paper feed cassette, and FIG. 4(b) shows the standby operation for such paper feed cassette.
In the example of conventional paper feed cassette shown in FIG. 4(a), a flat box-shaped cassette main body 1′ for storing paper has a bottom case 2′, a top cover 3′, and a support shaft 21′. The back end portions of the bottom case 2′ and top cover 3′ are coupled to each other via the support shaft 21′ that slidably engages a slot 31′, which is formed on the side of the top cover 3′ extending in the longitudinal direction of the top cover 3′. That way, the top cover 3′ is capable of sliding in the longitudinal direction “a” relative to the bottom case 2′. When paper is to be loaded into the cassette main body 1′, the top opening of the bottom cover 2′ can be opened by pivoting the top cover 3′ using the support shaft 21′ as a fulcrum. After the paper is loaded, the top opening of the bottom cover 2′ can be closed by pivoting the top cover 3′ using the support shaft 21′ as a fulcrum. When the top opening of the bottom cover 2′ is closed with the top cover 3′, a paper extraction port 12′ having a specific width opens between the front end of the bottom cover 2′ and the front end of the top cover 3′, as shown in FIG. 4(a).
Also, the front end of an auxiliary cover 4′, which functions as a catch tray in the longitudinal middle of the top cover 3′, is mounted to the top cover 3′ via a horizontal shaft 41′ so as to be pivotable forward and backward as indicated by the arrow “b”. The paper extraction port 12′ closes when the auxiliary cover 4′ is brought to a forward-tilted position, which his shown in the partially dotted line in FIG. 4(a). On the other hand, when the auxiliary cover 4′ is brought to an inclined backward-tilted position as shown by the solid line in FIG. 4(a), a top surface 42′, which is the inner surface of the auxiliary cover 4′, extends backward from the middle of the top surface portion 32′ of the top cover 3′, whereby a bent-shaped paper-receiving surface 5′ is formed by both of the top surfaces 42′ and 32′. The backward inclination of the auxiliary cover 4 is restricted by a part of the auxiliary tray 4′ coming into contact with the top cover 3′.
With the auxiliary cover 4′ in the backward-tilted position as shown in the solid line, the paper feed cassette is installed in the paper feed port 110′ of a printer or another such image-forming apparatus 100′ by inserting the front end of the cassette main body 1′ into the paper feed port 110′, in the direction shown by the arrow “a”. After the paper extracted from the paper extraction port 12′ is printed on by the operation of the image-forming apparatus in which the paper feed cassette is installed, the paper is ejected from a paper ejection port (not shown) of the image-forming apparatus 100′ onto the paper-receiving surface 5′ in the direction shown as arrow “c” in FIG. 4(b).
As is shown in FIG. 4(b), the paper P ejected from the paper ejection port of the image-forming apparatus 100′ onto the paper-receiving surface 5′ is held by the paper-receiving surface 5′ such that a portion around the area “D” is raised due to the rigidity of the paper P from the bent portion between the top surfaces 32′ and 42′. Accordingly, the paper P ejected onto the paper-receiving surface 5′ can be easily retrieved using the gap S formed between the paper-receiving surface 5′ and the paper P in the area D. In FIG. 4(b), θ indicates the angle formed between the top surface 32′ of the top cover 3′ and the top surface 42′ of the auxiliary cover 4′.
In the conventional examples described in FIG. 4, the auxiliary cover 4′ must be brought to a backward-tilted position as shown by the solid line in FIG. 4(a) to open the paper extraction port 12′ before the paper feed cassette is installed in the paper feed port 110′ of the image-forming apparatus 100′. Also, if the auxiliary cover 4′ is left in the backward-tilted position shown by the solid line in FIG. 4(a) after the paper feed cassette is removed from the image-forming apparatus, the paper extraction port 12′ stays open and dust adheres to the paper stored therein and soils the paper surface. This dust may cause printing quality deterioration or paper jams during the next printing cycle. Particularly, when the image-forming apparatus is a dye sublimation printer, glossy papers are often stocked in the paper feed cassette for high-quality printing. Therefore, it is extremely important to prevent soiling of the paper surface due to dust that enters onto the paper surface from the paper extraction port 12′. In order to prevent such soiling, the paper extraction port 12′ must be closed by pivoting the auxiliary cover 4′ so that dust does not adhere to the paper surface in the paper feed cassette after the paper feed cassette is removed from the paper feed portion 110′ of the image-forming apparatus 100′.
Therefore, as previously described, although the above-mentioned example of conventional paper feed cassette is meritorious in that the paper P ejected onto the paper-receiving surface 5′ is easily retrieved by utilizing the gap S formed above the bent portion of the paper-receiving surface 5′, the above-mentioned paper feed cassette also has problems in that the auxiliary cover 4′ must be tilted backward to the backward-tilted position to open the paper extraction port 12′ every time the paper feed cassette is to be installed in the paper feed port 110′ of the image-forming apparatus 100′. Similarly, the auxiliary cover 4′ must be tilted forward to close the paper extraction port 12′ every time the paper feed cassette is removed from the paper feed port 110′.
As an example of other conventional catch tray, it has been proposed in Japanese Patent Application Publication No. 59-167427 to provide a paper feed cassette feed for a copy machine in which the cover of the paper feed cassette is constantly biased in the closing direction, and when the cassette is installed in the copy machine the cover of the paper feed cassette as well as the paper feed port (paper extraction port) open. In another example, Japanese Patent Application Publication No. 6-156757 provides an image-forming apparatus which has a catch tray that is designed to close the top surface of a paper feed cassette as the paper feed cassette is inserted into the paper feed port of the image-forming apparatus. In still another example, Japanese Patent Application Publication No. 5-286579 discloses a paper feed cassette of which the top cover is installed in an image-forming apparatus and opened by the power from a motor installed also in the image-forming apparatus. In these examples, the cover described in Japanese Patent Application Publication No. 59-167427, the catch tray described in Japanese Patent Application Publication No. 6-156757, and the top cover described in Japanese Patent Application Publication No. 5-286579 all function as a catch tray.
The paper feed cassettes disclosed in Japanese Patent Application Publication Nos. 59-167427 and 5-286579 are both provided with functions of preventing dust from adhering to the surface of the paper stocked in the paper feed cassette by the cover or top cover. However, the paper-receiving surfaces defined by the top surface of the cover or top cover described above) are both formed to be flat. Therefore, these structures do not allow easy retrieval of the paper ejected onto the paper receiving surface, unlike the structure described above and shown in FIG. 4. More specifically, although the paper feed cassette shown in FIG. 4 allows the paper P ejected onto the paper-receiving surface 5 to be easily retrieved due to the gap S formed between the bent paper-receiving surface 5 and the paper P, the paper feed cassettes of Japanese Patent Application Publication Nos. 59-167427 and 5-286579 do not allow such easy retrieval of the paper because the paper-receiving surface is formed in a flat shape. The same problem also applies to the structure disclosed in Japanese Patent Application Publication No. 6-156757.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved paper feed cassette that overcomes the problems of the conventional art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.